Semiconductor Device With Trench Void For Low-Voltage Stress Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In the fabrication of semiconductor devices, stress is applied to the active region of low-voltage transistors when forming insulating films for high-voltage transistors, which can compromise their electrical characteristics.
Innovation Solution
A semiconductor device and method that include forming a device isolation region with a trench and a void connected to it, a mask pattern along the trench's sidewalls protruding inwardly, a gate insulating film along the void's sidewalls, and a gate electrode filling the trench and void, which reduces stress on the low-voltage transistor's active region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulating film for high voltage is formed in a recess trench of a high voltage transistor, then high voltage characteristics are maintained, but stress is applied to the active region of low voltage transistors
Solution Approach 1:
The patent applies local quality by forming the insulating film only in the recess trench of the high voltage transistor region, while excluding the low voltage transistor active region. The recess trench is selectively formed in the high voltage transistor's potential region, allowing the insulating film to be deposited locally where high voltage characteristics are needed, without affecting the low voltage transistor's active region. This spatial differentiation resolves the contradiction by concentrating the beneficial effect (high voltage characteristic) in the appropriate location while avoiding the harmful effect (stress on active region).
Solution Approach 2:
The patent segments the transistor structure by creating a recess trench that divides the high voltage transistor into distinct regions: a channel region above the trench and a potential region below. This segmentation allows the insulating film to be formed in the potential region without extending into the low voltage transistor's active region. The trench acts as a physical barrier that confines the insulating film formation to the high voltage transistor's designated area, thereby maintaining high voltage characteristics while protecting the low voltage transistor from stress.
2Reliability
If a recess trench is formed in a potential region to secure channel length, then high voltage characteristics are improved, but the fabrication process becomes more complex
Solution Approach 1:
The recess trench structure serves multiple functions simultaneously: it extends the channel length to maintain high voltage characteristics, provides a containment structure for the insulating film, and acts as a barrier to prevent stress propagation to low voltage transistors. By designing the recess trench to fulfill multiple roles, the patent reduces the need for additional separate structures or processes, thereby managing fabrication complexity while achieving the desired high voltage performance.
Solution Approach 2:
The patent employs a nested structure where the insulating film is formed within the recess trench, which itself is nested within the high voltage transistor's potential region. This nested arrangement allows the insulating film to be contained within the pre-formed trench structure, eliminating the need for separate film formation and patterning steps that would otherwise be required. The trench acts as a pre-defined container that guides the insulating film formation process, simplifying the overall fabrication sequence.
Data Source
AI summary
A semiconductor device and a method for fabricating the same are provided. The semiconductor device includes a device isolation region, a trench formed in the device isolation region, a void connected to the trench in the device isolation region, a first mask pattern formed along sidewalls of the trench and protruding inwardly with respect to the void, a gate insulating film formed along the sidewall of the void, and a gate electrode filling the trench and at least a portion of the void.